The treatment of exhaust gas from internal combustion engines with particulate filters and/or nitrogen oxide absorbers is known. In some systems, selective catalytic reduction (SCR) is used to convert nitrogen oxides into harmless molecules. For example, urea injection into the exhaust gas before passing through the catalytic converter can convert nitrogen oxides into N2, H2O and CO2, with thorough mixing of the exhaust gas with the urea critical in order to achieve high regeneration/conversion rates. However, most exhaust gas piping does not have a sufficient straight section prior to the catalytic converter and/or a particulate filter in order for the exhaust gas to be uniformly introduced to the converter and/or filter. As such a non-uniform field of temperature and/or reduction substance can develop and lead to reduced conversion rates in the converter. In addition, damage due to thermal distortions can occur in particulate filters.
Deflectors of exhaust gas are known to those skilled in the art. However, heretofore deflectors have had limited success and do not adequately deflect the exhaust gas over a variety of engine operating conditions. As such, an exhaust gas deflector that is variable and affords for uniform gas flow into a catalytic converter and/or particulate filer, despite changing exhaust gas parameters, would be desirable.